FDA: 13 PML Cases Confirmed in Tysabri Patients

The FDA says there have been 13 confirmed cases of progressive multifocal leukoencephalopathy (PML) in patients taking Biogen Idec and Elan Pharmaceuticals’ Tysabri for multiple sclerosis (MS) in the past three years. Biogen and Elan voluntarily suspended the marketing of Tysabri (natalizumab) in 2005 because of two PML brain infections in patients taking the drug. The drug was reintroduced in July 2006 under a restricted distribution program, and from that point until Sept. 8, 13 PML cases, four of them in the U.S., were confirmed in patients taking the drug as monotherapy for MS, the FDA says in a statement.
Drug Industry Daily